An electroactive conjugated oligomer for a direct electrochemical DNA sensor

• Published in: Synthetic metals 2012-10, Vol.162 (17-18), p.1496-1502
• Main Authors: Zhang, Q.D., Piro, B., Noël, V., Reisberg, S., Serradji, N., Dong, C.Z., Mameche, F., Pham, M.C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Biosensors; Biotechnology; Electroactive oligomer; Electrochemical sensor; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Label-free DNA sensor; Methods. Procedures. Technologies; Physicochemistry of polymers; Polymerization; Polymers and radiations; Quinone; Square wave voltammetry; Various methods and equipments
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2012.07.016

[Display omitted] ► Strategy to graft electroactive conjugated oligomers and DNA probes on an electrode. ► Label-free and reagentless DNA sensor. ► DNA strands interact with the electroactive oligomers and change their electroactivity. ► Hybridization leads to a current increase, whereas mismatch leads to no change. We report here an original strategy to graft both electroactive conjugated oligomers and DNA probes on an electrode to make a label-free and reagentless DNA sensor. Oligomers of 5-amino-1,4-naphthoquinone are synthesized, then covalently immobilized on the electrode by electro-oxidation of their terminal amino group, along with aminophenylacetic acid. Then, short DNA probes modified by terminal amino group are chemically grafted via peptide bonds on the aminophenylacetic acid molecules. In this way, short DNA strands and electroactive oligomers, having barely the same length, are grafted close together and can interact. It is shown that hybridization with a complementary sequence, which changes the conformation of DNA strands, influences the redox kinetics of quinone groups and leads to a current increase, whereas no significant changes are observed for random or mismatch sequences.